[PATCH v1 07/10] iio:adc:at91-sama5d2: Support backup mode

2017-09-08 18:03 GMT+02:00 Nicolas Ferre [off-list ref]:

On 08/09/2017 at 17:36, Romain Izard wrote:

quoted

Support the backup mode for platform suspend, by restoring the hardware
registers on resume.

Signed-off-by: Romain Izard <redacted>

Romain,

Thanks for your series: definitively some of your patches need to be
integrated (I've merged some of them in our current linux-4.9-at91 branch.
However, It seems that some of your additions have already been
submitted and/or accepted by maintainers.
For instance an equivalent of this one seems already in Linus' tree:
500a2eefd6b16ba141a8fb777ea6962d2eb65e3b ("iio: adc: at91-sama5d2_adc:
add support for suspend/resume functionality").

Please tell us if it fits what your observed on this driver (or others).

Regards,

quoted

---
 drivers/iio/adc/at91-sama5d2_adc.c | 71 ++++++++++++++++++++++++++++++++------
 1 file changed, 61 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index e10dca3ed74b..f9718c863363 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c

@@ -200,6 +200,7 @@ struct at91_adc_state {
      u32                             conversion_value;
      struct at91_adc_soc_info        soc_info;
      wait_queue_head_t               wq_data_available;
+     unsigned int                    current_rate;
      /*
       * lock to prevent concurrent 'single conversion' requests through
       * sysfs.

@@ -269,6 +270,8 @@ static void at91_adc_setup_samp_freq(struct at91_adc_state *st, unsigned freq)
      mr |= AT91_SAMA5D2_MR_PRESCAL(prescal);
      at91_adc_writel(st, AT91_SAMA5D2_MR, mr);

+     st->current_rate = freq;
+
      dev_dbg(&indio_dev->dev, "freq: %u, startup: %u, prescal: %u\n",
              freq, startup, prescal);
 }

@@ -375,7 +378,9 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
          val > st->soc_info.max_sample_rate)
              return -EINVAL;

+     mutex_lock(&st->lock);
      at91_adc_setup_samp_freq(st, val);
+     mutex_unlock(&st->lock);

      return 0;
 }

@@ -386,6 +391,21 @@ static const struct iio_info at91_adc_info = {
      .driver_module = THIS_MODULE,
 };

+static void at91_adc_init_hw(struct at91_adc_state *st, unsigned int freq)
+{
+     at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
+     at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
+     /*
+      * Transfer field must be set to 2 according to the datasheet and
+      * allows different analog settings for each channel.
+      */
+     at91_adc_writel(st, AT91_SAMA5D2_MR,
+                     AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
+
+     at91_adc_setup_samp_freq(st, freq);
+
+}
+
 static int at91_adc_probe(struct platform_device *pdev)
 {
      struct iio_dev *indio_dev;

@@ -482,16 +502,7 @@ static int at91_adc_probe(struct platform_device *pdev)
              goto vref_disable;
      }

-     at91_adc_writel(st, AT91_SAMA5D2_CR, AT91_SAMA5D2_CR_SWRST);
-     at91_adc_writel(st, AT91_SAMA5D2_IDR, 0xffffffff);
-     /*
-      * Transfer field must be set to 2 according to the datasheet and
-      * allows different analog settings for each channel.
-      */
-     at91_adc_writel(st, AT91_SAMA5D2_MR,
-                     AT91_SAMA5D2_MR_TRANSFER(2) | AT91_SAMA5D2_MR_ANACH);
-
-     at91_adc_setup_samp_freq(st, st->soc_info.min_sample_rate);
+     at91_adc_init_hw(st, st->soc_info.min_sample_rate);

      ret = clk_prepare_enable(st->per_clk);
      if (ret)

@@ -541,12 +552,52 @@ static const struct of_device_id at91_adc_dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, at91_adc_dt_match);

+#ifdef CONFIG_PM_SLEEP
+static int at91_adc_suspend(struct device *dev)
+{
+     struct platform_device *pdev = to_platform_device(dev);
+     struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+     struct at91_adc_state *st = iio_priv(indio_dev);
+
+     clk_disable_unprepare(st->per_clk);
+
+     regulator_disable(st->vref);
+     regulator_disable(st->reg);
+
+     return 0;
+}
+
+static int at91_adc_resume(struct device *dev)
+{
+     struct platform_device *pdev = to_platform_device(dev);
+     struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+     struct at91_adc_state *st = iio_priv(indio_dev);
+     int err;
+
+     err = regulator_enable(st->reg);
+     if (err)
+             return err;
+
+     err = regulator_enable(st->vref);
+     if (err)
+             return err;
+
+     at91_adc_init_hw(st, st->current_rate);
+
+     err = clk_prepare_enable(st->per_clk);
+     return err;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(at91_adc_pm_ops, at91_adc_suspend, at91_adc_resume);
+
 static struct platform_driver at91_adc_driver = {
      .probe = at91_adc_probe,
      .remove = at91_adc_remove,
      .driver = {
              .name = "at91-sama5d2_adc",
              .of_match_table = at91_adc_dt_match,
+             .pm = &at91_adc_pm_ops,
      },
 };
 module_platform_driver(at91_adc_driver)

Please ignore this patch. The existing merged patch is better.

Best regards,
-- 
Romain Izard